Other forms: firewalls
A firewall is the software or hardware that stands between a network and the outside world, letting some traffic through and blocking the rest. It is the standard first line of defence, and the one most people have heard of.
The name is borrowed from building, where a firewall is a solid wall built to stop a fire spreading from one part of a building to the next — and that is still what the word means to an architect or a fire officer. In a car, the firewall is the panel between the engine and the passengers. The figurative use has spread to money and politics: a financial firewall between two parts of a business, and in German politics a Brandmauer, the refusal of mainstream parties to work with the far right.
1nounfirewallSoftware or hardware that controls what traffic may pass between a network and the outside.
“The firewall blocked the connection before it reached the server.”
synonyms: barrier
2nounwallA wall built to stop fire spreading from one part of a building to another.
“The flats are separated by a firewall.”
3nounbarrierA barrier put between two parts of an organisation to stop trouble spreading.
“They built a firewall between the two funds.”
firewall is a barrier.
Firewall is simply fire plus wall, and it started in buildings. The car sense named the panel that separated the engine from the driver — and because the throttle linkage stopped there, pushing the pedal to the firewall meant giving it everything, which is where that phrase comes from.
From fire + wall. Compare West Frisian brânmuorre, Dutch brandmuur, German Brandmauer, Feuermauer, Swedish brandvägg, brandmur, Icelandic eldvegg. The verb sense for using maximum power or acceleration comes from the engine's firewall being the limit of forward movement of the throttle controls on many simpler vehicles; thus, to get the maximum engine output, one would push the throttle levers or pedal all the way to the firewall. The politics sense is a German Brandmauer.
Etymology from Wiktionary, CC BY-SA
Practised in Technology & Internet, Computing & Code